1. Technical Field
The present invention relates generally vehicle security systems and, more particularly, to a theft resistant system for vehicles incorporating starter-alternators.
2. Background Art
Combined Starter-Alternators (CSAs) are systems wherein the separate functions of engine cranking, performed by the starter motor, and electric energy generation, performed by the alternator, are combined into one 3-phase electric machine. Conventional starter motors are direct current electric machines whereas CSA systems are 3-phase alternating current electric machines. Conventional starter motors are powered directly from batteries, whereas 3-phase alternating current machines require power inverters (PI) that convert battery direct current into 3-phase alternating current.
Security systems are integrated into vehicles to prevent theft and are often embedded in the engine control module (ECM). Coded-key security systems operate by evaluating a key to determine if a specific engine start attempt is authorized. After proper authorization, the ECM activates both the fuel supply and the engine ignition system and closes the electric circuit that enables the starter motor to crank the engine.
If, however, proper authorization is not achieved, the fuel supply and ignition systems are disabled, the starter motor circuit is opened, and the vehicle is immobilized.
When the engine is immobilized, a new ECM with matching key is required to enable the vehicle to run. This results in significant cost and effort and acts as a deterrent for criminal activity. This deterrent would increase if the security system had the ability to disable other key vehicle systems that are costly to replace.
A primary limitation of the aforementioned security system is the ability to circumvent the electric circuit that enables engine cranking.
The limitation associated with current theft prevention techniques has made it apparent that a new technique to inhibit vehicle theft is needed. The new technique should substantially prevent circumvention of the electrical circuit that enables engine cranking and should increase vehicle component immobilization. The present invention is directed to these ends.
The present invention provides a theft resistant vehicle system. The present invention also provides a theft resistant system for vehicles equipped with combined starter-alternators.
In accordance with the present invention, a theft resistant vehicle system, including an activation unit adapted to generate a control signal as a function of an activation parameter, is disclosed. An alternating current power transfer unit is adapted to deactivate when no activation parameter control signal is received therein and is further adapted to generate an alternating current power signal in response to an activation parameter control signal. An electric machine receives the alternating current power signal.
One advantage of the current invention is that the electric machine is powered by alternating current and, by deactivating the activation unit when a deactivation parameter is met, alternating current is substantially prevented from reaching the electric machine. This inhibits activation of the electric machine through any other current sources.
Additional advantages and features of the present invention will become apparent from the description that follows and may be realized by the instrumentalities and combinations particularly pointed out in the appended claims, taken in conjunction with the accompanying drawings.